关键词: 土壤侵蚀, 土地利用类型, 林地适生程度, 区域分异, 气候变化, 泾河流域

Abstract: Located in the Loess Plateau, the Jinghe Watershed is an arid and semiarid area, where land use structure is dominated by grasslands with moderate or low vegetation coverage, and hilly farmland is an important factor resulting in severe water loss and soil erosion in the drainage basin. Therefore, the emphases of its ecological construction are to convert land for farming to forests or grassplots and improve vegetation coverage of the grasslands. According to the match degree of ecological water requirement of the local forestlands and local precipitation in growing season, in this paper, the Jinghe Watershed was divided into three kinds of areas: suitable or relatively suitable forestlands, relatively unsuitable forestlands, and unsuitable forestlands. The research results show that the three kinds of areas are distributed as sloped belts from northeast to southwest, and proportions of their areas were 53.69%, 22.16% and 24.15% of the total respectively. The climate change effects on regional differentiation of vegetation were analyzed. Precipitation in growth season of forestlands during the periods of 1961-1980 and 1981-2004 was compared and evaluated, and the corresponding change of regional differentiation of vegetation in the watershed was researched. It was found that precipitation in growth season of forestlands was in a decrease trend in most area of the Jinghe Watershed, and the most decrease was about 50 mm. Owing to the impact of precipitation change, the unsuitable and relatively unsuitable forestlands  were expanded southeastward, and the area of suitable or relatively suitable forestland was reduced by 11.4%. The study results can be referred  for regenerating local vegetation.

Key words: soil erosion, land use type, suitability of forestland, regional differentiation, climate change, Jinghe Watershed